1. Field of the Invention
The present invention relates to a construction of a tightening nut for mounting an air valve of an inner tube to a tire rim.
2. Description of the Prior Art
A conventional air valve mounting assembly for a tire A having an inner tube 3 is shown in FIG. 1. As shown in FIG. 1, an air valve stem 4 made predominantly of rubber is inserted into a valve hole 2 in a tire rim 1 for an inner tube 3, and a nut 4a is tightened onto the air valve 4 inside the tire rim 1 and another tightening nut 5 is tightened onto the air valve 4 provided outside the tire rim 1 so as to tightly mount the air valve 4 thereto.
A conventional air valve mounting construction for a tubeless tire B, as shown in FIG. 2, in which a snap-in type valve 8, for example, a rim valve, is mounted in removable engagement with a valve hole 7 provided in the tire rim 6. Generally, in conventional standardized goods, a diameter D.sub.1 of the valve hole 2 of the rim 1 provided for the inner tube tire A is smaller than a diameter D.sub.2 of the valve hole 7 of the rim 6 provided for the tubeless tire B.
When the bead portions of a tubeless tire are badly damaged, however, it is impossible to reuse the damaged tubeless tire as a tubeless tire. Such a damaged tubeless tire is usually reused by providing a new inner tube therein as if the tire was a tube tire. In this case, because the diameter D.sub.2 of the valve hole 7 of the rim 6 for the tubeless tire B is larger than the diameter D.sub.1 of the valve hole 2 of a rim of a corresponding tube tire A, it is necessary that another mechanical part 10, for example, a spacer, be inserted into the valve hole 7 in the tubeless tire rim 6 and the air valve 4 of the inner tube 3 be inserted through the spacer 10 and tightened down by the nut 5 through a washer 9, as shown in FIG. 3. Thus, tire-dealers, repair garages, gasoline stations and the like must always stock such spacers 10 and must expend additional work to mount the air valves 4 in the tubeless tire rim 6.